Optical characterizations of semiconducting β-FeSi2 films prepared by thermal annealing

Since β-FeSi₂ is a potential candidate for optoelectronic devices its optical properties have received recent attention of the researchers. We report here optical absorption and reflection, photoluminescence, FTIR, Raman and Micro Raman spectroscopy/mapping of β-FeSi₂ thin films on Si produced by thermal processing. Optical absorption and reflectance reveal that the material has a direct forbidden energy gap with appreciable sub band gap defect density. The photoluminescence was observed at 25 K but indicates a relative strain in the film, which is. further supported by Raman spectroscopy. Micro Raman mapping and spectra clearly indicates the formation of FeSi₂ along with some iron oxide.